The present invention relates in general to the design relationship between the radiator and the engine-driven fan for a water-cooled, internal combustion engine. More particularly, the present invention relates to the rigid mounting of the fan and fan cowling to the engine and the vibrational isolation of the radiator which is connected to the engine by way of a support frame.
In the design of a water-cooled, internal combustion engine attention must be given to the radiator and the engine-driven fan. There are certain desirable relationships which should improve cooling efficiency and contribute to reduced installation work. For example, the efficiency of cooling is dependent upon, among other factors, the size of the fan tip clearance between the ring of the fan cowling and the tips of the impeller blades. With regard to installation efficiencies, it would be an advantage to be able to supply and install the engine, fan, fan cowling and radiator as a single unit. The present invention provides a novel structural arrangement that satisfies both of the aforementioned desirable relationships.
One problem or concern with regard to the size of the clearance between the ring of the fan cowling and the tips of the impeller is when the fan cowling is rigidly connected to the radiator and is allowed to move relative to the fan when the system is subjected to vibration. In those known systems where the radiator is vibrationally isolated from the engine and the fan cowling is rigidly connected to the radiator, the fan blade (impeller tips) must be sized and positioned so that they do not contact the fan cowling. The easy solution is to build into the design sufficient clearance, but the greater the tip to cowling clearance the less efficient the design. Therefore it is preferred to design the fan and fan cowling relationship will a minimum of clearance so as to increase the efficiency of cooling.
In another known system the radiator and engine are separately mounted on and vibrationally isolated from the chassis or frame. The fan cowling is rigidly connected to the engine. In this system the engine, fan and fan cowling are free to move relative to the radiator when vibration occurs. A flexible coupling ring is provided between the fan cowling ring and the radiator. This system has the disadvantages that the radiator and engine must be separately supplied and filled to the chassis or frame and that the coupling ring takes up valuable space between the radiator and the engine.
Related and representative cooling systems known to the present inventors which the present invention improves upon include the following:
______________________________________ Patent No. Patentee Issue Date ______________________________________ 3,144,859 Walton August 18, 1964 4,086,886 Edmaier et al. May 2, 1978 4,213,426, Longhouse Jul. 22, 1980 4,398,508 Moon et al. Aug. 16, 1983 4,514,140 Knopf Apr. 30, 1985 4,522,160 Speers et al. Jun 11, 1985 4,774,911 Yamaguchi et al. Oct. 4, 1988 425,616 Bowman-Gr. Britain March 18, 1935 ______________________________________
In accordance with the present invention there is provided a radiator/fan mounting for a power unit comprising a water-cooled internal combustion engine, characterized in that the fan is rotatable in a housing assembly that is rigidly fixed to the engine and which resiliently supports the radiator.